The hepatoprotective effects of plant-based foods based on the "gut-liver axis": a prospective review.

The importance of the "gut-liver axis" in the pathogenesis of liver diseases has been revealed recently; which promotes the process of developing preventive and therapeutic strategies. However, considering that there are still many challenges in the medical treatment of liver diseases, potential preventive dietary intervention may be a good alternative choice. Plant-based foods have received much attention due to their reported health-promoting effects in targeting multiple pathways involved in the pathogenesis of liver diseases as well as the relative safety for general use. Based on the PubMed and Web of Science databases, this review emphatically summarizes the plant-based foods and their chemical constituents with reported effects to impact the LPS/TLR4 signaling pathway of gut-liver axis of various liver diseases, reflecting their health benefits in preventing/alleviating liver diseases. Moreover, some plant-based foods with potential gut-liver effects are specifically analyzed from the reported studies and conclusions. This review intends to provide readers an overview of the current progress in the field of this research topic. We expect to see more hepatoprotective measures for alleviating the current prevalence of liver diseases.

Marine Chitooligosaccharide Alters Intestinal Flora Structure and Regulates Hepatic Inflammatory Response to Influence Nonalcoholic Fatty Liver Disease.

In this study, C57BL/6 mice were given an HFHSD diet for 8 weeks to induce hepatic steatosis and then given COSM solution orally for 12 weeks. The study found that the HFHSD diet resulted in steatosis and insulin resistance in mice. The formation of NAFLD induced by HFHSD diet was related to the imbalance of intestinal flora. However, after COSM intervention, the abundance of beneficial bacteria increased significantly, while the abundance of harmful bacteria decreased significantly. The HFHSD diet also induced changes in intestinal bacterial metabolites, and the content of short-chain fatty acids in cecal contents after COSM intervention was significantly higher than that in the model group. In addition, COSM not only improved LPS levels and barrier dysfunction in the ileum and colon but upregulated protein levels of ZO-1, occludin, and claudin in the colon and downregulated the liver LPS/TLR4/NF-κB inflammatory pathway. We concluded that the treatment of marine chitooligosaccharide COSM could improve the intestinal microflora structure of the fatty liver and activate an inflammatory signaling pathway, thus alleviating the intrahepatic lipid accumulation induced by HFHSD.

Costunolide protects against alcohol-induced liver injury by regulating gut microbiota, oxidative stress and attenuating inflammation in vivo and in vitro.

Costunolide (cos) derived from the roots of Dolomiaea souliei (Franch.), which belongs to the Dolomiaea genus in the family Compositae, exert the anti-inebriation effect mainly by inhibiting the absorption of alcohol in the gastrointestinal tract. However, the protective effect of cos against alcohol-induced liver injury (ALI) remains obscure. The present study was aimed to evaluate the hepatoprotective effects of cos (silymarin was used as positive control) against ALI and its potential mechanisms. MTT was used to examine the effect of cos on the cell viability of L-02 cells. Plasma was separated from blood that used to test the levels of TNF-α, IL-6 and IL-12, and LPS while serum separated from blood which used to detect the level of ALT and AST. Liver tissues were obtained for histopathological examination and western blot analysis. Fresh mice feces samples were collected for the detection of bacterial composition. Cos exhibited protective effect against alcoholic-induced liver injury by regulating gut microbiota capacities (higher relative abundance of Firmicutes and Actinobacteria while lower in Bacteroidetes and Proteobacteria), adjusting oxidative stress (reduced the activities of MDA and ROS while promoted SOD, GSH and GSH-PX in L-02 cells) and attenuating inflammation (decreased the levels of ALT, AST, LPS, IL-6, IL-12 and TNF-α) via LPS-TLR4-NF-κB p65 signaling pathway, which might be an active therapeutic agent for treatment of ALI.

ACE2 exhibits protective effects against LPS-induced acute lung injury in mice by inhibiting the LPS-TLR4 pathway.

This study aimed to investigate the protective effect of angiotensin converting enzyme 2 (ACE2) on lipopolysaccharide (LPS)-induced acute lung injury (ALI). After generating ALI mouse models by injecting LPS, the levels of ACE2, inflammatory factors, and downstream proteins of the LPS-TLR4 pathway were analyzed. LPS-challenged BEAS-2B cells were established in vitro. Next, a eukaryotic expression vector, pm-ACE2, was constructed and validated. Challenged cells were transfected with pm-ACE2 containing enhanced green fluorescent protein, or they were treated with D-Ala-Ang-(1-7), angiotensin converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB) and the LPS-TLR4 pathway inhibitor dimethyl fumarate (DMF) for analysis of how the above factors contribute to ACE2 regulation. Expression of renin, Ang II, ACE and angiotensin II type 1 receptor (AT1R) was subsequently assessed. In the ALI model, mice exhibited decreased expression of ACE2, lung pathological injury, inflammatory injury, and abnormal activation of the LPS-TLR4 pathway. LPS-challenged BEAS-2B cells demonstrated upregulated expression of renin, Ang II, ACE and AT1R. After injection of ACE2, lung function and lung pathological injury were significantly improved, and that effect was accompanied by attenuated inflammation, and inactivation of the LPS-TLR4 pathway. Cell studies showed similar results. The above observations were further enhanced when there was a combined treatment with DMF and pm-ACE2. D-Ala-Ang-(1-7) treatment attenuated the protective effect of ACE2, while ACEI and ARB treatment alleviated LPS-induced pneumonic injury. In conclusion, ACE2 was expressed at low levels in response to LPS-induced ALI. Overexpression of ACE2 regulates the ACE2/Ang-(1-7)/Mas and ACE/Ang II/AT1 axes to maintain dynamic balance of the renin-angiotensin system, and attenuate inflammatory response.

Inulin Ameliorates Alcoholic Liver Disease via Suppressing LPS-TLR4-Mψ Axis and Modulating Gut Microbiota in Mice.

BACKGROUND: Alcoholic liver disease (ALD) represents a chronic liver disorder caused by alcohol abuse. Numerous studies have demonstrated that gut microbiota dysbiosis plays a critical role in ALD pathogenesis. Application of prebiotic, probiotic, and dietary supplementation to the modulation of gut microbiota contributes to a novel approach to the management of ALD. Inulin, a natural prebiotic found in plants, can restore gut dysbiosis in ALD. However, the exact mechanism of dietary inulin in ALD remains largely unknown. METHODS: Sixty female C57BL/6J mice were randomly divided into 4 groups: pair-fed (PF) group (PF/CON); alcohol-fed (AF) group (AF/CON); PF with inulin (INU) group (PF/INU); and AF with INU group (AF/INU). All mice were fed with isocaloric modified Lieber-DeCarli liquid diets with or without alcohol. RESULTS: After 6 weeks of feeding, mice were euthanized and associated indications were investigated. The results showed that chronic ethanol (EtOH) intake led to the loss of body weights, abnormal levels of transaminases, and inflammatory indicators (lipopolysaccharide [LPS], interleukin [IL]-6, IL-10, tumor necrosis factor-α, IL-17A), while inulin administration ameliorated these effects. To further understand the underlying mechanism, we investigated macrophages (Mψs) and gut microbiota in diverse groups. The number of Mψs was reduced after dietary inulin treatment in chronic EtOH exposure. Hepatic Toll-like receptor 4 (TLR4+ ) Mψs in AF/INU group were lower than AF/CON group. 16S rRNA sequencing and analysis of gut microbiota indicated the reduction of Allobaculum, Lactobacillus, and Lactococcus, as well as the increase of Parasutterella in AF group compared with PF control. Increased Allobaculum, Lactobacillus, and Lactococcus but reduced Parasutterella in AF/INU group were confirmed that dietary inulin rectified gut dysbiosis to attenuate ALD. CONCLUSIONS: Dietary inulin ameliorates ALD via suppressing LPS-TLR4-Mψ axis and modulating gut microbiota in mice, thus potentially provides theoretical foundation for inulin intervention in the prevention and treatment of ALD.

High-mobility group box 1 inhibits HCO(3)(-) absorption in medullary thick ascending limb through a basolateral receptor for advanced glycation end products pathway.

High-mobility group box 1 (HMGB1) is a damage-associated molecule implicated in mediating kidney dysfunction in sepsis and sterile inflammatory disorders. HMGB1 is a nuclear protein released extracellularly in response to infection or injury, where it interacts with Toll-like receptor 4 (TLR4) and other receptors to mediate inflammation. Previously, we demonstrated that LPS inhibits HCO(3)(-) absorption in the medullary thick ascending limb (MTAL) through a basolateral TLR4-ERK pathway (Watts BA III, George T, Sherwood ER, Good DW. Am J Physiol Cell Physiol 301: C1296-C1306, 2011). Here, we examined whether HMGB1 could inhibit HCO(3)(-) absorption through the same pathway. Adding HMGB1 to the bath decreased HCO(3)(-) absorption by 24% in isolated, perfused rat and mouse MTALs. In contrast to LPS, inhibition by HMGB1 was preserved in MTALs from TLR4(-/-) mice and was unaffected by ERK inhibitors. Inhibition by HMGB1 was eliminated by the receptor for advanced glycation end products (RAGE) antagonist FPS-ZM1 and by neutralizing anti-RAGE antibody. Confocal immunofluorescence showed expression of RAGE in the basolateral membrane domain. Inhibition of HCO(3)(-) absorption by HMGB1 through RAGE was additive to inhibition by LPS through TLR4 and to inhibition by Gram-positive bacterial molecules through TLR2. Bath amiloride, which selectively prevents inhibition of MTAL HCO(3)(-) absorption mediated through Na⁺/H⁺ exchanger 1 (NHE1), eliminated inhibition by HMGB1. We conclude that HMGB1 inhibits MTAL HCO(3)(-) absorption through a RAGE-dependent pathway distinct from TLR4-mediated inhibition by LPS. These studies provide new evidence that HMGB1-RAGE signaling acts directly to impair the transport function of renal tubules. They reveal a novel paradigm for sepsis-induced renal tubule dysfunction, whereby exogenous pathogen-associated molecules and endogenous damage-associated molecules act directly and independently to inhibit MTAL HCO(3)(-) absorption through different receptor signaling pathways.

LPS antagonism of TGF-ß signaling results in prolonged survival and activation of rat primary microglia.

Accumulating evidence indicates that activated microglia contribute to the neuropathology involved in many neurodegenerative diseases and after traumatic injury to the CNS. The cytokine transforming growth factor-beta 1 (TGF-ß1), a potent deactivator of microglia, should have the potential to reduce microglial-mediated neurodegeneration. It is therefore perplexing that high levels of TGF-ß1 are found in conditions where microglia are chronically activated. We hypothesized that TGF-ß1 signaling is suppressed in activated microglia. We therefore activated primary rat microglia with lipopolysaccharide (LPS) and determined the expression of proteins important to TGF-ß1 signaling. We found that LPS treatment decreased the expression of the TGF-ß receptors, TßR1 and TßR2, and reduced protein levels of Smad2, a key mediator of TGF-ß signaling. LPS treatment also antagonized the ability of TGF-ß to suppress expression of pro-inflammatory cytokines and to induce microglial cell death. LPS treatment similarly inhibited the ability of the TGF-ß related cytokine, Activin-A, to down-regulate expression of pro-inflammatory cytokines and to induce microglial cell death. Together, these data suggest that microglial activators may oppose the actions of TGF-ß1, ensuring continued microglial activation and survival that eventually may contribute to the neurodegeneration prevalent in chronic neuroinflammatory conditions.

Gut microbiome-mediated monocytes promote liver metastasis.

The gut microbiome plays an important role in tumor growth by regulating immune cell function. However, the role of the gut microbiome-mediated monocytes in liver metastasis remains unclear. In this study, we found that fecal microbiome transplantation (FMT) from the stool of patients with liver metastasis (LM) significantly promoted liver metastasis compared with healthy donors (HD). Monocytes were upregulated in liver tissues by the CCL2/CCR2 axis in LM patients' stool transplanted mouse model. CCL2/CCR2 inhibition and monocyte depletion significantly suppress liver metastasis. FMT using LM patients' stool enhanced the plasma lipopolysaccharides (LPS) concentration. The LPS/TLR4 signaling pathway is crucial for gut microbiome-mediated liver metastasis. These results indicated that monocytes contribute to liver metastasis via the CCL2/CCR2 axis.

The role of innate and adaptive immunity in endometriosis.

The innate and adaptive immune systems are the two key branches that determine host protection at all mucosal surfaces in human body, including the female reproductive tract. The pattern recognition receptors within the host that recognize pathogen-associated molecular patterns are expressed on the cells of the innate immune system. Rapidly reactive, theinnate immune system, responds immediately to the presence of infectious or other non-self agents, thereby launching an inflammatory response to protect the host until the activation of slower adaptive immune system. Macrophages, dendritic cells, and toll-like receptors are integral components of the innate immune system. In contrast, T-helper (Th1/Th2/Th17) cells and regulatory T (Treg) cells are the primary components of adaptive immune system. Studies showed that the growth and progression of endometriosis continue even in unilateral ovariectomized animal suggesting that besides ovarian steroid hormones, the growth of endometriosis could be regulated by innate/adaptive immune systems in pelvic environment. Recent reports demonstrated a potential role of Th1/Th2/Th17/Treg cells either individually or collectively in the initiation, maintenance, and progression of endometriosis. Herewe review the fundamental knowledge of innate and adaptive immunity and elaborate the role of innate and adaptive immunity in endometriosis based on both human and experimental data.

Exploring the efficacy and mechanism of Bailing capsule to improve polycystic ovary syndrome in mice based on intestinal-derived LPS-TLR4 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with reproductive dysfunction and metabolic abnormalities, particularly characterized by insulin resistance and chronic low-grade inflammation. Multiple clinical studies have clearly demonstrated the significant efficacy and safety of the combination of Bailing capsules (BL) in the treatment of PCOS, but its pharmacological effects and mechanisms still require further study. AIM OF THE STUDY: To evaluate the effect of BL on improving PCOS in mice and explore the mechanism. METHODS: In this study, Dehydroepiandrosterone (DHEA) injection was administered alone and in combination with a high-fat and high-sugar diet to induce PCOS-like mouse. They were randomly divided into five groups: normal group (N), PCOS group (P), Bailing capsule low-dose group (BL-L), Bailing capsule high-dose group (BL-H) and Metformin + Daine-35 group (M + D). Firstly, the effects of BL on ovarian lesions, serum hormone levels, HOMA-IR, intestinal barrier function, inflammation levels, along with the expression of IRS1, PI3K, AKT, TLR4, Myd88, NF-κB p65, TNF-α, IL-6, and Occludin of the ovary, liver and colon were investigated. Finally, the composition of the gut microbiome of fecal was tested. RESULTS: The administration of BL significantly reduced body weight, improved hormone levels, improved IR, and attenuated pathological damage to ovarian tissues, up-regulated the expression of IRS1, PI3K, and AKT in liver. It also decreased serum LPS, TNF-α, and IL-6 levels, while downregulating the expression of Myd88, TLR4, and NF-κB p65. Additionally, BL improved intestinal barrier damage and upregulated the expression of Occludin. Interestingly, the abundance of norank_f__Muribaculacea and Lactobacillus was down-regulated, while the abundance of Akkermansia was significantly up-regulated. CONCLUSION: The results of the study showed that BL exerts a treatment PCOS effect, which may be related to the modulation of the gut microbiota, the improvement of insulin resistance and the intestinal-derived LPS-TLR4 inflammatory pathway. Our research will provide a theoretical basis for the clinical treatment of PCOS.

The Combination of Bacillus natto JLCC513 and Ginseng Soluble Dietary Fiber Attenuates Ulcerative Colitis by Modulating the LPS/TLR4/NF-κB Pathway and Gut Microbiota.

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) that is currently difficult to treat effectively. Both Bacillus natto (BN) and ginseng-soluble dietary fiber (GSDF) are anti-inflammatory and helps sustain the intestinal barrier. In this study, the protective effects and mechanism of the combination of B. natto JLCC513 and ginseng-soluble dietary fiber (BG) in DSS-induced UC mice were investigated. Intervention with BG worked better than taking BN or GSDF separately, as evidenced by improved disease activity index, colon length, and colon injury and significantly reduced the levels of oxidative and inflammatory factors (LPS, ILs, and TNF-α) in UC mice. Further mechanistic study revealed that BG protected the intestinal barrier integrity by maintaining the tight junction proteins (Occludin and Claudin1) and inhibited the LPS/TLR4/NF-κB pathway in UC mice. In addition, BG increased the abundance of beneficial bacteria such as Bacteroides and Turicibacter and reduced the abundance of harmful bacteria such as Allobaculum in the gut microbiota of UC mice. BG also significantly upregulated genes related to linoleic acid metabolism in the gut microbiota. These BG-induced changes in the gut microbiota of mice with UC were significantly correlated with changes in pathological indices. In conclusion, this study demonstrated that BG exerts protective effect against UC by regulating the LPS/TLR4/NF-κB pathway and the structure and metabolic function of gut microbiota. Thus, BG can be potentially used in intestinal health foods to treat UC.

Inulin alleviates perinatal 2-ethylhexyl diphenyl phosphate (EHDPHP) exposure-induced intestinal toxicity by reshaping the gut microbiota and suppressing the enteric-origin LPS/TLR4/NF-κb pathway in dams and pups.

Organophosphorus flame retardants (OPFRs), such as 2-ethylhexyl diphenyl phosphate (EHDPHP), are ubiquitously used, leading to pervasive environmental contamination and human health risks. While associations between EHDPHP and health issues such as disruption of hormones, neurotoxic effects, and toxicity to reproduction have been recognized, exposure to EHDPHP during perinatal life and its implications for the intestinal health of dams and their pups have largely been unexplored. This study investigated the intestinal toxicity of EHDPHP and the potential for which inulin was effective. Dams were administered either an EHDPHP solution or a corn oil control from gestation day 7 (GD7) to postnatal day 21 (PND21), with inulin provided in their drinking water. Our results indicate that inulin supplementation mitigates damage to the intestinal epithelium caused by EHDPHP, restores mucus-secreting cells, suppresses intestinal hyperpermeability, and abates intestinal inflammation by curtailing lipopolysaccharide leakage through reshaping of the gut microbiota. A reduction in LPS levels concurrently inhibited the inflammation-associated TLR4/NF-κB pathway. In conclusion, inulin administration may ameliorate intestinal toxicity caused by EHDPHP in dams and pups by reshaping the gut microbiota and suppressing the LPS/TLR4/NF-κB pathway. These findings underscore the efficacy of inulin as a therapeutic agent for managing health risks linked to EHDPHP exposure.

Da-yuan-yin decoction alleviates ulcerative colitis by inhibiting complement activation, LPS-TLR4/NF-κB signaling pathway and NET formation.

ETHNOPHARMACOLOGICAL RELEVANCE: Da-yuan-yin decoction (DYY) is a classical traditional Chinese medicine prescription for ulcerative colitis (UC). AIM OF STUDY: This study explored the protective effects and mechanisms of DYY on UC. MATERIALS AND METHODS: The mice were fed 2.5% dextran sulfate sodium (DSS) for 7 days to establish UC. On the second day, DYY (0.4 g/kg, 0.8 g/kg, 1.6 g/kg) was orally administered daily for 7 consecutive days. The colon tissues and serum were measured by histopathological examination and biochemical analysis. RESULTS: DYY significantly reduced the disease activity index (DAI) and severity of colon shortening and alleviated pathological changes in the colon tissue. DYY restored the protein expression of intestinal tight junction (TJ) protein (ZO-1, occludin and claudin-3). DYY remarkably decreased the level of lipopolysaccharide (LPS), Lactic acid (LA), circulating free DNA (cfDNA), complement (C3, C3a, C3c, C3aR1, C5a and C5aR1) and regulated the levels of inflammatory cytokines in serum. DYY significantly inhibited the expressions of nuclear factor kappa-B p65 (NF-κB p65) and Toll-like receptor 4 (TLR4), citrullinated histone H3 (CitH3) and myeloperoxidase (MPO), reactive oxygen species (ROS) peptidylarginine deiminase 4 (PAD4) and CD 11b, the mRNA levels of PADI4, MPO and ELANE in colon tissues. CONCLUSIONS: DYY significantly attenuated DSS-induced UC, which was related with regulating the inflammatory response by the inhibition of complement activation, the LPS-TLR4/NF-κB signaling pathway and neutrophil extracellular traps (NETs) formation. DYY is a potential therapeutic agent for UC.

Sulforaphane Ameliorates Nonalcoholic Fatty Liver Disease Induced by High-Fat and High-Fructose Diet via LPS/TLR4 in the Gut-Liver Axis.

The gut-liver axis has emerged as a key player in the progression of non-alcoholic fatty liver disease (NAFLD). Sulforaphane (SFN) is a bioactive compound found in cruciferous vegetables; however, it has not been reported whether SFN improves NAFLD via the gut-liver axis. C57BL/6 mice were fed a high-fat and high-fructose (HFHFr) diet, with or without SFN gavage at doses of 15 and 30 mg·kg-1 body weight for 12 weeks. The results showed that SFN reduced weight gain, hepatic inflammation, and steatosis in HFHFr mice. SFN altered the composition of gut microbes. Moreover, SFN enhanced the intestinal tight junction protein ZO-1, reduced serum LPS, and inhibited LPS/TLR4 and ERS pathways to reduce intestinal inflammation. As a result, SFN protected the intestinal integrity and declined the gut-derived LPS translocations to the liver in HFHFr diet-induced mice. SFN decreased the liver LPS levels and inhibited the LPS/TLR4 pathway activations, thus inhibiting the pro-inflammatory cytokines. Notably, Spearman correlation analysis showed that the protective effect of SFN on intestinal barrier integrity and its anti-inflammatory effect on the liver was associated with improved intestinal dysbiosis. Above all, dietary intervention with SFN attenuates NAFLD through the gut-liver axis.

Modulation of Xiongdanjiuxin pills on the gut-liver axis in high-fat diet rats.

AIM: Xiongdanjiuxin pill (XP) is a traditional Chinese medicine formula for the prevention and treatment of hyperlipidemia (HLP) and related complications. In this study, the gut-liver axis was used as the breakthrough point to analyze the therapeutic effect and potential mechanism of XP on HLP model rats and related complications. MAIN METHODS: We used high-fat diet (HFD) to establish the HLP model of rats and treated them with XP. The 16S rRNA sequencing method was used to explore the effect of XP on the gut microbiota of HFD rats, and the effects of XP on ileum pathology, intestinal barrier and circulatory inflammation in HFD rats were also investigated. We further explored the molecular mechanism of XP treating liver inflammation in rats with HFD by regulating toll-like receptor 4 (TLR4) signaling. KEY FINDINGS: We found that XP could regulate the imbalance of gut microbiota in HFD rats, and up-regulate the expression of tight junction protein in intestinal epithelium of HFD rats, thereby improving the intestinal barrier damage and intestinal inflammatory response. In addition, XP could significantly reduce the levels of inflammatory cytokines in HFD rats, and inhibit TLR4 signaling pathway, thereby reducing liver inflammation in HFD rats. SIGNIFICANCE: XP can effectively improve the imbalance of gut-liver axis in hyperlipidemic rats and alleviate the inflammatory damage of liver. Its mechanism may be related to regulating the disorder of gut microbiota and inhibiting TLR4 signal pathway, so as to achieve the therapeutic effect on hyperlipidemic fatty liver in rats.

Naotaifang III Protects Against Cerebral Ischemia Injury Through LPS/TLR4 Signaling Pathway in the Microbiota-Gut-Brain Axis.

Background: Ischemic stroke (IS) is a leading cause of mortality worldwide. Naotaifang III is a new Chinese herbal formula to treat IS. Previous studies have shown that Astragali Radix, Puerariae Lobatae Radix, Chuanxiong Rhizoma, and Rhei Radix Et Rhizoma in Naotaifang III were able to regulate the imbalance of intestinal microbiota during cerebral ischemia injury. Methods: Rats were randomly divided into sham operation group, normal control group, middle cerebral artery occlusion (MCAO) group, intestinal microbiota imbalance MCAO group, Naotaifang III group, and normal bacteria transplantation group, with 15 rats in each group. Then, neurological function scores and cerebral infarction volume were detected; haematoxylin and eosin staining and Golgi silver staining were used to observe morphological changes in brain tissue. Meanwhile, the lipopolysaccharide (LPS) and cerebral cortex interleukin (IL)-1ß were detected by enzyme-linked immunosorbent assay (ELISA); the expressions of Toll-like receptor (TLR)-4 and nuclear factor kappa-B (NF-κB) proteins were detected by immunofluorescence and Western blot. The cecal flora was detected by 16S rDNA. The results showed that gut dysbiosis aggravated cerebral ischemic injury and significantly increased the expression of LPS, TLR4, NF-κB, and IL-1ß, which could be significantly reversed by Naotaifang III or normal bacterial transplantation. Naotaifang III may exert a protective effect on neuroinflammatory injury after MCAO through the LPS/TLR4 signaling pathway in the microbe-gut-brain axis. In summary, Naotaifang III may induce anti-neuroinflammatory molecular mechanisms and signaling pathways through the microbe-gut-brain axis. Results: The results showed that gut dysbiosis aggravated cerebral ischemic injury and significantly increased the expression of LPS, TLR4, NF-κB, and IL-1ß, which could be significantly reversed by Naotaifang III or normal bacterial transplantation. Naotaifang III may exert a protective effect on neuroinflammatory injury after MCAO through the LPS/TLR4 signaling pathway in the microbe-gut-brain axis. Conclusion: Naotaifang III may induce anti-neuroinflammatory molecular mechanisms and signaling pathways through the microbe-gut-brain axis.

Nomilin Attenuates Lipopolysaccharide-Induced Inflammatory Response by Binding with Myeloid Differentiation Protein-2.

BACKGROUND: Nomilin shows anti-inflammatory activity by inhibiting the activation of the Toll-like receptor 4 (TLR 4)/NF-κB pathway. However, the key target of the anti-inflammatory activity of nomilin has not been elaborated and needs further exploration. OBJECTIVE: This study aimed to assess the drug potential of nomilin and its ability to target myeloid differentiation protein 2 (MD-2) as a mechanism underlying the anti-inflammatory activity of nomilin on the lipopolysaccharide (LPS)-TLR4/MD-2-NF-κB signaling pathways. METHODS: The methods of ForteBio and molecular docking were used to investigate the internation between MD-2 and nomilin. 3-(4,5)-Dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide experiment was performed to test the effect of nomilin on cell viability. Enzyme-linked immunosorbent assay, real-time polymerase chain reaction, and Western blot experiments were carried out to assess the anti-inflammatory activity and possible mechanism of nomilin in vitro. RESULTS: The results indicated that nomilin exhibited binding affinity with MD-2. Nomilin significantly reduced the release and expression of NO, IL-6, TNF-α, and IL-1ß induced by LPS in vitro. It inhibited the expression of LPS-TLR4/MD-2-NF-κB signaling pathway proteins, such as TLR4, Myd88, P65, P-P65, and iNOS. CONCLUSION: Our results suggested that nomilin had therapeutic potential and was bound to MD-2. Nomilin exhibited anti-inflammatory activity by binding to the key protein MD-2 and inhibiting the LPS-TLR4/MD-2-NF-κB signaling pathway.

Dityrosine Aggravates Hepatic Insulin Resistance in Obese Mice by Altering Gut Microbiota and the LPS/TLR4/NF-κB Inflammatory Pathway.

SCOPE: Dityrosine is the main product of protein oxidation, which has been proved to be a threat to human health. This study aims to investigate whether dityrosine exacerbates insulin resistance by inducing gut flora disturbance and associated inflammatory responses. METHODS AND RESULTS: Mice fed with normal diet or high-fat diet (HFD) received daily gavage of dityrosine (320 µg kg-1 BW) or saline for consecutive 13 weeks. The effects of dityrosine on gut microbiota are verified by in vitro fermentation using fecal microbiota from db/m mice and db/db mice. As a result, dityrosine causes the insulin resistance in mice fed normal diet, and aggravates the effects of HFD on insulin sensitivity. Dityrosine increases the levels of lipopolysaccharide (LPS), lipopolysaccharide-binding protein (LBP), toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) but decreases levels of interleukin-10 (IL-10) in the plasma of CON and HFD-fed mice. The changes of gut flora composition caused by dityrosine are significantly correlated with the changes of inflammatory biomarkers. CONCLUSION: The effects of dityrosine on insulin resistance may be attributed to the reshaping of the gut microbiota composition and promoting the activity of the LPS/TLR4/NF-κB inflammatory pathway in HFD-induced obese individuals.

Effects of Bu Shen Hua Zhuo formula on the LPS/TLR4 pathway and gut microbiota in rats with letrozole-induced polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in gynecology. Traditional Chinese medicine (TCM) is widely used for the treatment of PCOS in China. The Bu Shen Hua Zhuo formula (BSHZF), a TCM decoction, has shown great therapeutic efficacy in clinical practice. However, the mechanism underlying the BSHZF function in PCOS remains unclear. This study aimed to identify the potential mechanisms of action of BSHZF in the treatment of PCOS. PCOS-model rats treated with letrozole were administered different doses of BSHZF, metformin, and 1% carboxymethylcellulose. Serum sex hormones, fasting blood glucose, and fasting insulin levels were measured, and the morphology of the ovaries was observed in each group, including the normal group. The structure and abundance of the gut microbiota in rats were measured using 16S ribosomal RNA gene sequencing. Toll-like receptor 4 (TLR4) and phospho-NF-κB p65 levels in the ovarian tissue of the rats were detected using Western blotting. Furthermore, the levels of lipopolysaccharide (LPS) and inflammatory cytokines TNF-α, IL-6, and IL-8 in the serum of rats were detected by ELISA. The results showed that BSHZF administration was associated with a decrease in body weight, fasting blood glucose, fasting insulin, and testosterone and changes in ovarian morphology in PCOS-model rats. Moreover, BSHZF was associated with an increase in the α-diversity of gut microbiota, decrease in the relative abundance of Firmicutes, and increase in Lactobacillus and short chain fatty acid-producing bacteria (Allobaculum, Bacteroides, Ruminococcaceae_UCG-014). Furthermore, BSHZF may promote carbohydrate and protein metabolism. In addition, BSHZF was associated with a decrease in the serum level of LPS and TLR4 expression, thereby inhibiting the activation of the NF-κB signaling-mediated inflammatory response in ovarian tissue. Therefore, the beneficial effects of BSHZF on PCOS pathogenesis are associated with its ability to normalize gut microbiota function and inhibit PCOS-related inflammation.

Smilax china L. flavonoid alleviates HFHS-induced inflammation by regulating the gut-liver axis in mice.

BACKGROUND: Smilax china L., a traditional Chinese herb, has been used to treat various inflammatory disorders, particularly pelvic inflammation. The anti-inflammatory activity of the plant extract has been reported in several in vivo experimental models. However, the underlying anti-inflammatory mechanisms and the role of gut microbiota in mice on Smilax china L. flavonoid (SCF) treatment are poorly understand. PURPOSE: To investigate the role of SCF in providing the anti-inflammatory response and the role of gut microbiota in high-fat/high-sucrose (HFHS)-induced obese mice for 12 weeks. STUDY DESIGN AND METHODS: C57BL/6J mice were randomly divided into seven groups, normal chow (NC), HFHS, Orlistat, SCE, and low-, medium-, high- doses of SCF for 12 weeks. The body weight, liver weight, serum concentrations of lipopolysaccharide (LPS), and inflammatory cytokines in mice were assessed. The gene and protein expression levels of inflammation-related markers were measured by qRT-PCR and Western blot. Finally, the composition of gut microbiota was detected by analyzing 16S rDNA gene sequences. RESULTS: SCF supplement reduced body weight gain, adipose tissue and liver indexes, attenuated serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, LPS, and increased IL-10, and adiponectin. SCF significantly reduced the mRNA expression levels of TNF-α, IL-6, and increased the expression of AMPK, PPAR-γ, and IL-10 in mice's liver and adipose tissues. In addition, the TLR4, p-IκBα, NF-κB, and p65 protein expression levels were reduced after the SCF supplement. Moreover, SCF treatment ameliorated HFHS-induced gut dysbiosis, as revealed by an increased intestinal barrier protective species (Akkermansia spp). The relative abundance of Streptococcaceae, Faecalibaculum, and endotoxin-producing Desulfovibrionaceae were significantly decreased on SCF supplements. CONCLUSION: The results showed that SCF effectively inhibits HFHS-induced inflammation by suppressing the LPS-producing bacteria and pro-inflammatory bacteria group. Furthermore, the abundance of gut barrier protective species Akkermansia spp was increased to alleviate inflammatory response, inhibiting the LPS-TLR4/NF-κB signaling pathway. Thus, SCF may be a promising prophylactic for diet-induced inflammatory diseases through the gut-liver axis in mice.